Grinding machine



Oct. 31, 1933. H. K. TEGARDEN GRINDING MACHINE Filed Nov. 19, 1931 2Sheets-Sheet l Oct. 31, 1933. TEGARDEN 1,932,993

GRINDING MACHINE Filed Nov. 19, 1931 2 Sheets-Sheet 2 Patented Oct. 31,1933 UNITED STATES PATENT OFFICE GRINDING MACHINE Application November19, 1931 Serial No. 576,108

13 Claims.

This invention relates to improvements in machine tools and especially,to improvements in grinding machines.

One of the principal objects of this invention is the provision of agrinding machine for grinding work pieces normally difficult to rotatedue to their mass'or their tendencyv to twist when a driving force isapplied to one end thereof.

A further object of the invention is the provision of a grinding machinefor rotating work from opposite ends thereof and in which the drivingtorque between two ends is equalized.

Another object of the invention is the provision of animproved doubleend drive in which the driving torque is transferred from one end to theother for equalizing the driving torque on the work.

These and other objects are obtained by the means illustrated in theaccompanying drawings and described in the following specification andit is to be understood that any modifications may be made in the exactstructural details there shown ancl'described within the scope of theappended claims without departing from or exceeding the spirit of theinvention.

In the drawings:

Figure 1 is a front elevation of a grinding machine embodying theimprovements of this invention. v

Figure 2 is a sectional view taken on line 2-2 of Figure 1.

Figure 3 is a sectional view taken on line 33 of Figure 1.

Figure 4 is a sectional view taken on line 44 of Figure 2.

Figure 5 is a diagrammatic illustration of the several component partsof the invention.

Throughout the several views of the drawings.

similar reference characters areemployed to denote the same or similarparts.

While the invention is capable of general use for grinding comparativelylong slender cylindrical work pieces as well as heavy rolls, it has beenillustrated in connection with a machine for grinding crank shafts. Ineach of these work pieces it is necessary and essential that the workbevro tated about a definite axis and that the twist therein be held toan absolute minimum. At-

tempts have been made to drive the work from both ends, but considerabledifficulty has been experienced in, trying to balance or equalize thedriving torque at the said ends. This invention obviates thesedifliculties and equalizes the driving torque so that a constantrotation of the work is had about a definite unvarying axis.

A machine embodying this invention may comprise a bed 10 having formedon the upper end thereof guideways 11 for the work supporting table 12for guiding said table longitudinally of, the bed 10. The bed is furtherprovided with ways forthe grinding wheel carriage 13 which supports aspindle for the grinding wheel 14 enclosed within a suitable guard orthe like 15 carried by the carriage 13. The carriage l3 and grindingwheel are adapted to be fed laterally of the bed 10 toward and from thework table 12, for which purpose a feeding mechanism indicated in thedrawings by the numeral 16 is provided. The table 12 supports atopposite ends thereof a head stock 17 and a tail stock 18 from whichproject the spindles l9 and 20. The head stock 17 supports a prime moveror motor 21, which rotates a pinion '22 secured to its shaft 23. A shaft24 mounted in the head stock 17 has secured to its inner end a sprocket25. A gear chain 26 is trained about the sprockets 22 and 25 forrotating the shaft 24 at the desired speed, which is or may be varied bychanging the ratio between the sprockets 22 and 25. The other end of theshaft 24 has formedthereon or secured thereto a worm 27 meshing with aworm Wheel 28 'on one 'end of a jack shaft 29.. The shaft 29 isjournaled in suit- 35 able bearings extending from the table 12 so thatsaid shaft moves with the table. The shaft 29 is in two parts, beingconnected together by a separable coupling 30-for a purpose that willlater appear.

The jack shaft 29 has secured to opposite ends thereof sprocket chaingears 31 and 32, the former being adjacent the head stock 17, while thelatter is nearthe tail stock 18. A sprocket chain 33' extends about thegear-31 as well as about a gear 95 34 loosely journaled on the spindle19. A chuck head or crank shaft fixture 35 is secured to one end of thespindle 19 and forms one abutment for the loose gear 34 and limits themovement of the gear longitudinally of the spindle '19 inone direction.A collar 35 is secured to the spindle '19 on V the other side of thegear 34 and limits its move-. ment in the other direction. Projectingfrom one face of the gear 34 is a driving pin 37, adapted to engage apiston rod or pin 38 projecting outwardly from a cylinder 39 secured toface plate 40, which is in turn fastened to the head stock spindle 19.

The chain gear 32 at the other end of the shaft 29 has also extendingabout it a sprocket 1 chain 41 which is trained about a gear 42 loose onthe tail stock spindle 20. A chuck or crank shaft fixture 43 is securedto the outer end of the tail stock spindle 20, to which the other end ofthe work piece 44 is secured. The gear 42, similar to the gear 34, hasprojecting from it a driving pin 45 adapted to contact with a piston rodor pin 46 projecting outwardly from a cylinder 47 secured to a faceplate 48 in turn fastened to the tail stock spindle 20. The tail stockspindle is also connected with an adjusting screw 49 operated by a handwheel 50 whereby the axial position of the tail stock spindle 20 may beeffected. The chuck or crank shaft fixture 43 and a collar 51 co-operateto limit the axial movement of the driving gear 42 relative to the tailstock spindle 20.

From the foregoing it will be noted that the rotation of the jack shaft29 will through the gear chains 33 and 41 effect simultaneous rotationof the gears 34 and 42, which through their inter-engagement with pistonrods or pins 38 and 46 rotate the spindles 19 and 20.

Each of the cylinders 39 and 47 enclose a piston 52 movable therein foractuating the piston rods or pins 38 and 46. The construction about tobe described is the same at each end and it is, therefore, deemedsufiicient if but one of the driving mechanisms or dogs be describedindetail. Accordingly, the cylinder 39 has its one end closed by a heador cap 53 through which a port 54 is formed. A conduit or pipe 55extends from the port 54 and terminates at a port 56 formed radially inthe spindle 19. The cylinder 39 is provided on its other end with a port57 from which a pipe 58 extends, likewise terminating at a port 59formed in the spindle 19. A channel 60 extends from the port 56longitudinally of the spindle 19 from which a radial port 61 projects.The port 61 is aligned with a circumferential groove 62 formed on theinner surface of a ring 63 which surrounds the spindle 19. The ring 63is provided on its exterior surface with a second groove 64 which alignswith a port 65 formed through the bearing portion of the head stock 1'7.A conduit 66 extends from the port 65 to a conduit 66A which terminatesin the base of a tank or sump 6'7 mounted on the head stock 17containing an hydraulic medium, preferably oil. The port 59 alsoconnects with a channel 68 extending longitudinally of the spindle 19having a radial port 69 at one end thereof projecting outwardly of thespindle 19. The port 69 is also aligned with a recess '70 formed on theinside of a ring '71 surrounding the spindle 19. A

second recess '72 on the outer surface of the ring '70 affordscommunication with a port 73 formed in the head stock 17. A conduit '74extends from this port and is connected to the base of the tank 6'7 by abranch conduit 74A.

From the foregoing it will be noted that any oil or other hydraulicmedium within the tank 67 flows by gravity from the conduits 66 and '74filling the channels 60 and 68 and the cylinder 39 on opposite sides ofthe piston 52. The conduits 66 and 74 continue to the tail stock end ofthe table 12, where they are similarly connected with the spindle 20 forfilling .the cylinder 47 on opposite sides of the piston containedtherein.

The figures 2 and 3 illustrate the driving pins of the head and tailstocks as contacting with the pistons on opposite sides of the axialcenter of the work so that a movement of the gears 34 and 42 in thedriving direction will rotate the work in the same direction. Theoperation of the mechanism is as follows. A work piece is mountedbetween the head and tail stock spindles and clamped to the chucks orfixtures 35 and 43. The motor 21 is then rotated for effecting rotationof the jack shaft 29. This shaft 29 immediately initiates movement ofthe gears 34 and 42 causing the driving pins thereof to engage thepiston pins 38 and 46. Should one of the piston pins be projectingslightly beyond the other pin, the following operation will result.Assuming the head stock piston pin 38 to contact with the driving pin37, it will be forced inwardly of its cylinder, forcing the hydraulicmedium behind its piston 52 from the cylinder through the conduit 55,ports and channels, 56, 60 and 61, through the conduit 66 to the tailstock spindle where it will connect behind its associated piston forforcing it outwardly to meet the driving pin 45 of the tail stock gear.This movement will continue until an equal pressure is had on the rearface of each of the pistons whereupon the unitary rotation of the dogswill result. Should, for any reason, one of the dogs attempt toout-drive the other or assume a greater load, the torque thereof will beimmediately transferred through the hydraulic lines to the other drivingmechanism. From this it will be seen that the driving connections willimmediately balance themselves as far as the torque is concerned forrotating the work at a constant rotation and eliminating all possibletwist within the work.

By reference to Figure 4 it will be noted that the head stock bearinghas secured therein a sleeve '77 which forms a bearing for the spindle19. The end of the sleeve '77 nearest the ring 63 is inclined oppositelythe inclination of the adjacent face of said ring. In the space betweenthese opposed inclined faces is mounted a packing member '78 whichprevents leakage of the hydraulic medium along the spindle toward thechuck or fixture secured thereto. The opposed faces of rings 63 and '71are inclined in opposite directions to one another and have mountedbetween them a packing member '79 which prevents leakage of thehydraulic medium from the rings into the said space between said rings.The remaining face of the ring '71 is also inclined which is in adirection opposite to the direction of inclination of the adjacent faceof a packing gland which is threaded into the end of the spindlebearing. In the space between the opposed faces of ring '71 and gland 80a packing member 81 is positioned to prevent leakage of the hydraulicmedium along the spindle toward the rear end thereof. The end 82 of thegland 80 is of an angular cross section for the reception of a wrenchwhereby the gland may be screwed into the spindle bearing. It will benoted that the inclined faces of the gland 80, rings 63 and '71 andsleeve '77 co-operate with one another to force the packing members '78,'79 and 31'into close contact with the outer surface of the spindle.

In the event it is desired to drive only from the front end of themachine, it is only necessary to loosen the coupling 30 therebyeffectively dsconnecting the tail stock drive and the other end. Toinsure no interference from the tail stock "end of the machine-'whendriving solely from the head stock endthereof, choke valves 83 and 84may be respectively provided for the lines 66 and '74. r

Whatis claimed is:

i '1. In a grinding machine of the class described the combinationofabed, a work supporting table mounted thereon, means supporting the workon the table, driving means at'each end of the table each comprisingafreely rotatable member, a fixed member connected to the dr-i-vingmeans, a yieldable coupling bet-ween each-pair of loose and fixedmembers of the drivefand means checking the yieldable coupling of onepair and transferring the driving torque to the other pair for balancingthe driving torque of each member. A

2. In a grinding machine of the class described the combination of abed, atable mounted thereon for supporting a work piece, means ateachend for simultaneously rotating the work, and means for balancing thedriving torque of said rotating means comprisinga piston and cylinderassociated with each driving means at each end of the work, a closedhydraulic circuit between the pistons and cylinders, and means in thehydraulic circuit for balancing the driving torque between each pistonand cylinder.

3. In a grinding machine of the class described the combination of abed, a table mounted thereon for supporting a work piece, means at eachend for simultaneously rotating the work, and means for balancing thedriving torque of said members comprising a piston and cylinder at eachend, a closed hydraulic circuit between the pistons and cylinders, meansfor balancing the driving torque between each piston and cylinder, and acommon activating means for the driving members.

4. In a grinding machine the combination of a bed, a grinding wheelrotatably mounted thereon, means supported by the bed for supporting awork piece for rotation adjacent the active face of the grinding wheel,means for rotating the work at each end thereof comprising a membersecured to the supporting means at each end thereof, a freely rotatingmember adjacent each fixed member, a coupling between the loose andfixed members, and means equalizing the driving torque between the looseand fixed members.

5. In a grinding machine the combination of a bed, means supporting thework at each end comprising a spindle, means rotatably supporting eachspindle, a member loosely journaled on each spindle, a second membersecured to each spindle, a driving dog on each loose member, a companiondog secured to the fixed member of each spindle, means forsimultaneously rotating the loose members relative to the spindles, andmeans for equalizing the driving torque! between the dogs and theircompanion members.

6. In a grinding machine the combination of a bed, means supporting thework at each end comprising a spindle, means rotatably supporting eachspindle, a member loosely journaled on each spindle, a second membersecured to each spindle, a driving dog on each loose member, a companiondog secured to the fixed member of each spindle, means forsimultaneously rotating the loose members relative to the spindles,means for equalizing the driving torque between the dogs and theircompanion members, said means comprising a closed hydraulic circuitbetween the companion members, and

a' piston' associated with' each of the companion members fortransferring the-torque of lone through the hydraulic circuit to theother.

7. In a grinding machine the combination of a bed, meanssHppo'rting thework'at each-end comprising a' spi-ndle, means rotatably support ingeach spindle, amemberloosely journaled on each spindle, a second membersecured to each spindle, a driving i dog on-each loose member, acompanion dog secured to the dried memberof each :spindla means forsimultaneously: rotating the loose members relative to the spindles,means for equalizing the driving torque between the dogs and theircompanion membe'rs, said means "comprising a closed h ydraulic circuitbetween the companion members, a piston-associatedwith each of thecompanion members for transferring-the torque of one through thehydraulic circuit "to the other, and meansfor maintainingthe closedcircuit primed. 7

8. In a double end drive for grinding'machines and the. like thecombination of .a. :spindle at each end of aawork piece and operativelyvconnected therewith for rotation: thereby,- a driving-member associatedwith*ea'ch spindle but normally disconnected therefrom, a common powersource for rotating said members, a driven member associated with eachspindle and connected thereto, a driving dog between each driven memberand driving member, and means equalizing the driving torque between thedriving dogs.

9. In a double end drive for grinding machines and the like thecombination of a spindle at each end of a work piece and operativelyconnected therewith for rotation thereby, a driving member associatedwith each spindle but normally disconnected therefrom, a common powersource for rotating said members, a driven member associated with eachspindle and connected thereto, a driving dog between each driven memberand driving member, means equalizing the driving torque between thedriving dogs, said means including a closed hydraulic circuit betweenthe dogs, and a piston associated with each dog for transferring thedriving torque to the other dog through the hydraulic medium.

10. In a double end drive for grinding machines and the like thecombination of a spindle at each end of a work piece and operativelyconnected therewith for rotation thereby, a driving member associatedwith each spindle but normally disconnected therefrom, a common powersource for rotating said members, a driven member associated with eachspindle and connected thereto, a driving dog between each driven memberand driving member, means equalizing the driving torque between thedriving dogs, said means including a closed hydraulic circuit betweenthe dogs, a piston associated with each dog for transferring the drivingtorque to the other dog through the hydraulic medium, and means formaintaining the hydrauliccircuit filled at all times.

11. In a double end drive for grinding machines and the like thecombination of a spindle at each end of a work piece and operativelyconnected therewith for rotation thereby, a driving member associatedwith each spindle but normal- 1y disconnected therefrom, a common powertween the dogs, a piston associated with each dog for transferring thedriving torque to the other dog through the hydraulic medium, means for.maintaining the hydraulic circuit filled at all times, said meanscomprising a tank, an hydraulic medium within the tank, and meanspermitting a flow of the hydraulic medium from the tank to the closedhydraulic circuit but preventing a reverse flow of the medium.

12. In a double end drive for grinding machines or the like thecombination of a bed, a head stock supported by the bed, a tail stocksupported by the bed, a spindle associated with each stock, a gearloosely journaled on each spindle, a driven shaft, means connecting theshaft and gears for simultaneous rotation of the gears, a face platesecured to each spindle, a driving pin projecting from each gear, adriven dog projecting from each face plate, each dog comprising acylinder and piston, a piston pin projecting from each piston forengagement with its associated driving pin of the gear, conduits betweenthe cylinders, and an hydraulic medium in the cylinders and conduitswhereby the driving torque on one of the dogs is transferred to theother dog equalizing the driving torque thereon.

13. In a double end drive for grinding machines or the like thecombination of a bed, a head stock supported by the bed, a tail stocksupported by the bed, a spindle associated with each stock, a gearloosely journaled on each spindle, a driven shaft, means connecting theshaft and gears for simultaneous rotation of the gears, a face platesecured to each spindle, a driving pin projecting from each gear, adriven dog projecting from each face plate, each dog comprising acylinder and piston, a piston pin projecting from each piston forengagement with its associated driving pin of the gear, conduits betweenthe cylinders, an hydraulic medium in the cylinders and conduits wherebythe driving torque on one of the dogs is transferred to the other dogequalizing the driving torque thereon, a tank for the hydraulic medium,connections between the tank and conduits for supplying the hydraulicmedium to the conduits, and means associated with the connections forpreventing the flow of the medium from the conduits into the tank.

HERBERT K. TEGARDEN.

